Chipperman: Have you read the regulations? Here's the url to the regs:
http://www.ago.state.ma.us/cmr2.pdf
Regarding the melting point thing, that is in section 16.04 (1). It says that you can't sell a new handgun if the frame, barrel, cylinder, or breech block is "composed of any METAL having a melting point of less than 900 degrees." The HK USP polymer frame is clearly not composed of metal, and thus the melting point does not apply.
Nevertheless, read on down to section 16.04 (3). This section states that 16.04(1) does not apply to any gun which meets the Make and Model Performance Requirements.
Folks, please READ the regulations. They're not very long.
Jared
PS. No, I'm not defending the regulations. I think they are ludicrous. Just trying to correct some misconceptions.